Bottle cases or crates with pockets for locating and separating bottles have been in wide use, and have had essentially flat bottoms for stacking on the tops of bottles in like cases for storage. Such cases of wood, metal, and/or plastic construction wherein the cases are of considerably less height than the bottles are disclosed in U.S. Pat. Nos. 2,293,893, 2,667,284, and 3,107,026. Such cases were reasonably satisfactory for many years, but demands for safety, waste reduction, and better utilization of floor space for storage have combined with the availability of fork lift trucks and palletized storage methods to point up the problems with these cases, mainly their tendency to slide around on each other when stacked up, whether containing full or empty bottles, or even when stacked empty of bottles. Stacking loaded cases five or six layers high on pallets, and then perhaps stacking loaded pallets atop one another for fork lift truck transport and storage, is full of danger from cases knocked off the stacks by passing personnel, vehicles, or palletized loads; not to speak of the disadvantages of the necessity for building perfect stacks and handling them very gently so that cases do not slide off or out of the stacks during palletized transport and storage with the ensuing tilting and joggling of the stacks, though interlocked but without positive engagement.
In order to form more stable columnar stacks using such cases, intermediate supports as disclosed in U.S. Pat. No. 1,747,408 have been provided to act as fillers in the vertical spaces between stacked cases. These supports fit telescopically with both upper and lower cases for stability, and also prevent the upper cases from resting on the tops of bottles in the lower cases, but they are not attractive because of the extra initial cost, handling, and storage involved, as well as the accurate registry required during stacking, and no simultaneous interlocking.
Other cases or crates have had side walls higher than the bottles, so that the cases stack upon themselves rather than upon the bottles underneath, and likewise have only flat bottoms with no provision for stabilizing a stack; such a case is shown in U.S. Pat. No. 2,830,729.
Other bottle cases, such as those disclosed in U.S. Pat. Nos. 2,758,742 and 3,380,616, have had side walls higher than the bottles, and their tops and bottoms have been formed for telescopic engagement when stacked, so that they would form reasonably stable columnar stacks, but with no provision for interlocking stacks for maximum stability. Cases of this type require correspondingly more material for manufacture, and are heavier and bulkier for shipment without bottles than lower cases, and are heavier for handling both empty and full, as well as bulkier for empty storage. Stacking of such cases requires accurate placement to achieve proper telescopic engagement, and of course this is difficult in the rough handling environment of the usual bottle distribution and re-use system.
Thus, while the bottle cases of the first and third paragraphs of this Background were incapable of forming positively locked-together, stable stacks, and those of the second and fourth paragraphs telescope in columns only without provision for simultaneous interlocking stacking, through separate filler pieces or comparatively larger and heavier cases all requiring accurate placement of the cases, the cases of the present invention allow positively interlocked stacking of filled cases in a variety of completely stable stack configurations without requiring excessively accurate placement of the cases on the stacks, the empty cases also telescope, and the bulk and weight of the empty cases is kept to a minimum. The present invention includes all the advantages of the prior art, omits the disadvantages of the prior art, and introduces advantages of its own such as self-centering action in a stack.
Bottle cases according to the present invention overcome these problems with a minimal weight and usage of material and provide positive lateral engagement directly with the bottles of other cases when stacked one upon another, and thereby form very stable stacks with no possibility of one case sliding from atop the bottles of another case. These cases also allow positively interlocked stacking in "pinwheel" or other stack forms with the same positive lateral engagement for extra stable stacking similar to interlocking brickwork. These cases do not require accurate positioning of one case on another when filled with bottles--if reasonably well located over the bottles underneath (just well enough to engage bottle tops and case recesses), any shaking or joggling of the upper cases causes them to act in self-centering fashion on the bottles beneath, and the stack assumes a more regular form whether stacked in columnar or interlocking fashion. Cases according to the present invention are light and small for ease of handling and shipping, have provision made in tops and bottoms for telescopic columnar stacking when empty, and occupy correspondingly less volume when so stacked then the previous telescoping full bottle height cases.